pdp1@EARTHLINK.NET on thu 15 sep 05
----- Original Message -----
From: "Craig Clark"
<<<<<<<>>>>>
> If you don't want to go down this avenue then just cut out the
opening in your roof as if you were framing in a skylight. Then frame in the
area with steel rather than wood. Use a coupla pieces that are space some
inches apart so as to mitigate heat transfer. Once you have established a
miny steel structure of this nature in the immediate vicinity of your
venting system you will not longer be in violation of the way your code is
written. You won't have an 18 inch hole in your roof and the inspector
should be happy.
> Hope this helps
> Craig Dunn Clark
Hi Craig, all...
If 18 inches is the required clearance FROM the stack, then the diameter or
size of the chimney or stack in it's outside dimensions, is the from-where
the "18 inches" begins on each side, and all around it.
Hence, if say a 10 inch round stack, the "hole" for it would have to be 41
inches in diameter, not "18" inches...which is 18 inches on all sides from
the O.D. of the stack or chimney...
Thats quite a big hole!
Love,
Phil
las vegas
Craig Clark on fri 16 sep 05
pdp1@EARTHLINK.NET wrote:
>
>Hence, if say a 10 inch round stack, the "hole" for it would have to be 41
>inches in diameter, not "18" inches...which is 18 inches on all sides from
>the O.D. of the stack or chimney...
>
>Thats quite a big hole!
>
>
>Love,
>
>Phil
>las vegas
>
>
>
>
Phil, all, yes I understand. I was not being specific enough with
the alternative that I was suggesting. The "framing out as if one were
framing for a sky light" was meant to suggest a method. The origianl
framed hole will indeed seem quite large. It would be at least 30x30.
More than likely 36x36 depending upon the spacing between the rafters.
The idea is to go out far enough, frame the opening size that is
sufficient, and then to cut out portions of the existing wooden rafters,
and roof within the confines of the "offending" space. Then to use steel
as rafters with the framed area, perlons, and then to sheeth with steel
roofing material (I would use corrugated with a nice profile.) Or any
decent fabrication shop could fashion a piece of galvanized or other
through which the chimney could then pass. I still wouldn't get overly
close to the chimmney with even the steel rafters.
It is also important to be sure to use a good storm collar around
the chimney that will withstand the heat as well as to flash from under
the storm collar to below and atop the roofing steel. The under is for
the high side and the atop is for the low. Sorry about not be more
specific. I was in a bit of a rush in that I find myself chasing my butt
in ever widening circles these days...LOL
Hope this helps
Craig Dunn CLark
619 East 11 1/2 st
Houston, Texas 77008
(713)861-2083
mudman@hal-pc.org
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